Friday, July 10, 2009

Final journey for massive bridge joints

Posted for Jeff Switzer

To be honest, I'm feeling a little jealous of the two new expansion joints bound for the I-90 floating bridge. They've already seen more of the world this year than I will!

They were created in Ohio, painted in Pittsburgh and assembled back in Ohio using special Teflon bearings made in Turkey. They were hauled thousands of miles across the U.S. to the Seattle waterfront where they waited until the big moment.

Friday marked the final journey for the joints (pdf 720 KB), each weighing 65 tons and measuring 65 feet long. The two joints got a pretty sweet tour of Seattle before going to work on the I-90 floating bridge. It was no Argosy Cruise past Bill Gates' house, but there's no stopping the barge Los Angeles, tended by the tugboats Crown II and Redwood City. Instead of the longer-than-advertised three-hour tour on Gilligan's Island, the trip was expected to be a more dependable six hours from the Seattle waterfront to the I-90 floating bridge.

Along the way, the joints followed the Duwamish and gave tourists an eyeful as they climbed through the Hiram M. Chittenden Locks to Lake Washington. News helicopters planned to film the trip from high above the city streets. Drawbridges across Seattle saluted as the barge and joints passed beneath at a 4 mph walker's pace.

Like putting a heavy box of holiday decorations away on a top shelf, it’s no easy feat to lift the giant joints from Lake Washington onto the I-90 floating bridge. It takes a massive barge 250 feet long and 75 feet wide to haul the joints and a seven-story-tall behemoth of a crane to the I-90 work zone.

The crane stretched its even longer 173-foot boom to deliver the joints to crews on the bridge. After hours of maneuvering, the joints sit in a cradle of rebar and are locked into place with tons of concrete.

These stronger, thicker joints allow the floating bridge to flex with the wind and water and span the westbound lanes of the I-90 floating bridge and the bicycle pedestrian path. They replace their lesser cousins that began cracking soon after they were installed 20 years ago.

It's a complicated choreography for construction. At the same time, drivers face their own two-step as they slog through the construction bottleneck we put in the I-90 freeway to get 70,000 daily drivers around the work zone.

In about a week, we'll all start pummeling the new joints daily. The road reopens by July 20, and for the next 50 or more years the joints will signal their presence to millions of everyday drivers with the familiar “vrrrp – vrrrp” as they drive across Lake Washington to Seattle.

It took months to create these special 65-foot-long joints for this special bridge. Pieces were bolted, welded and connected with strong rubber gaskets meant to last. Despite their long journey from the Midwest, they never traveled I-90. Instead, tractor trailers opted for I-70 and I-75 out of Ohio, I-80 from Cheyenne to Utah, and later I-5 from Vancouver.

And when the autumn winds pick up, storms again will paint whitecaps across the lake. The joints will flex with every powerful surge, but keep the bridge deck connected to Seattle and Mercer Island, and traffic will continue to flow safely. Whenever I drive my kids across the bridge, I'll tell them, "did you know what it took to get these joints into place? Let me tell you ..."